The Relation of Weight Loss and Improved Fitness to Survival in Healthy Males
Obesity is a critical public health problem because of its prevalence, medical and psychosocial effects, and resistance to intervention. Weight loss in overweight individuals has been encouraged by the United States Public Health Service and by the medical community as a means for improving health. However, recent studies have suggested either positive or negative effects of weight loss on survival. It is possible that physical fitness may have a confounding effect, or be an effect modifier on survival in weight loss studies. This study used Cox Regression analysis to address the separate and combined association of weight loss and improved fitness to all-cause mortality. A two-visit, apparently healthy, initially low fit, overweight male subset (n = 1,616), age 20 to 65 years, from the Aerobics Center Longitudinal Study was selected. Males were grouped according to the following weight and fitness change combinations between first and second visits: 1. Weight same, fitness same; 2. Weight same, fitness increase; 3. Weight loss, fitness same; 4. Weight loss, fitness increase. The risk of those who maintained their obese condition was not significantly worse than the risk of those who reduced their weight (RR = 1.8; 95% CI = .3 - 11.4). The risk for those who maintained their low fitness was 8.9 times higher than the risk of those who improved their fitness (RR = 8.9; 95% CI = 1.3 - .58.4). The reduced risk associated with improved fitness was not significantly stronger for those who lost weight than for those who maintained their obese status. Supported by NIH AG06945
Preventive Medicine, Public Health, Weight Loss; Physical Fitness.
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